It is proposed to identify approximately 3000 white males in each of two cohorts who can be found in both the 1880 and 1900 U.S. censuses. Individuals will be sampled randomly from the 1880 census and tracked to their appearance in 1900 using the 1900 Soundex. The 1900 census is the only census with a suitable Soundex system; 1880 and 1900 are the two most recent complete censuses in the public domain. Complete data on the sampled individuals and their associated households will be coded. The data will be edited, linked to existing, aggregate-level data files for 1880 and 1900, documented, and made available to other researchers. We propose also to analyze the data with respect to individual change in occupation, residence, and household characteristics across the 20 year spa, as well as associations between these changes and contextual variables, etc. The data refer to a period of great development in American society through the forces of industrialization, urbanization, waves of immigration, westward expansion, and fertility decline. This will be the first data set from the period which (a) is national rather than local, and (b) follows individuals rather than being cross-sectional.